Web Framework

A web framework (WF) or web application framework (WAF) is a software framework that is designed to support the development of web applications including web services, web resources, and web APIs. Web frameworks provide a standard way to build and deploy web applications on the World Wide Web. Web frameworks aim to automate the overhead associated with common activities performed in web development. For example, many web frameworks provide libraries for database access, templating frameworks, and session management, and they often promote code reuse. Although they often target development of dynamic web sites, they are also applicable to static websites.

History

As the design of the World Wide Web was not inherently dynamic, early hypertext consisted of hand-coded HTML text files that were published on web servers. Any modifications to published pages needed to be performed by the pages' author. In 1993, the Common Gateway Interface (CGI) standard was introduced for interfacing external applications with web servers, to provide a dynamic web page that reflected user inputs.

Original implementations of the CGI interface typically had adverse effects on the server load however, because each request started a separate process. More recent implementations utilize persistent processes amongst other techniques to reduce the footprint in the server's resources and offer a general performance boost.

In 1995, fully integrated server/language development environments first emerged and new web-specific languages were introduced, such as ColdFusion, PHP, and Active Server Pages.

Although the vast majority of languages for creating dynamic web pages have libraries to help with common tasks, web applications often require specific libraries for particular tasks, such as creating HTML (for example, Jakarta Server Faces).

In the late 1990s, mature, "full stack" frameworks began to appear, that often gathered multiple libraries useful for web development into a single cohesive software stack for web developers to use. Examples of this include ASP.NET, Java EE, WebObjects, web2py, OpenACS, Catalyst, Mojolicious, Ruby on Rails, Laravel, Grails, Django, Zend Framework, Sails.js, Yii, CakePHP, and Symfony.

Types of framework architectures

Most web frameworks are based on the model–view–controller (MVC) pattern.

Model–view–controller (MVC)

Many frameworks follow the MVC architectural pattern to separate the data model into business rules (the "controller") and the user interface (the "view"). This is generally considered a good practice as it modularizes code, promotes code reuse, and allows multiple interfaces to be applied. In web applications, this permits different views to be presented, for example serving different web pages for mobile vs. desktop browsers, or providing machine-readable web service interfaces.

Push-based vs. pull-based

Most MVC frameworks follow a push-based architecture also called "action-based". These frameworks use actions that do the required processing, and then "push" the data to the view layer to render the results. Django, Ruby on Rails, Symfony, Spring MVC, Stripes, Sails.js, CodeIgniter are good examples of this architecture. An alternative to this is pull-based architecture, sometimes also called "component-based". These frameworks start with the view layer, which can then "pull" results from multiple controllers as needed. In this architecture, multiple controllers can be involved with a single view. Lift, Tapestry, JBoss Seam, Jakarta Server Faces, and Wicket are examples of pull-based architectures.
Play, Struts, RIFE, and ZK have support for both push- and pull-based application controller calls.

Three-tier organization

In three-tier organization, applications are structured around three physical tiers: client